The present invention relates generally to seats for mass transit vehicles such as railroad commuter cars and more particularly to walkover seats for such vehicles.
A walkover seat is one in which a seat back may be moved from the front end to the rear end of the seat to allow the seat occupant or passenger to face whichever direction the occupant desires. It also allows two adjacent seats in a row of seats to be arranged so that the occupants of the two seats face each other in a group, when the occupants desire such an arrangement. A walkover seat allows one to reposition the seat back to one's liking, creating forward facing, rearward facing or a group cluster of seats.
A walkover seat employs pivotal linkages between the seat back and the frame of the seat to accomplish the walkover movement and employs other linkages to change the inclination of the seat cushion in response to repositioning of the seat back. Examples of walkover seats employing such linkages are shown in Kehl et al U.S. Pat. No. 4,407,542, and in Bilancia U.S. Pat. No. 3,265,435, and the disclosures thereof are incorporated herein by reference.
There have been walkover seats which did not employ any provision for locking the backrest in either of its two rest positions. In one respect, this was advantageous because it allowed the seat back to be repositioned at will, without the need to actuate release levers, pedals, linkages or switches normally associated with locking mechanisms. This made it very convenient for passengers or train personnel to reposition the seat back, but it had other drawbacks.
More particularly, in the case of an abrupt stop, as in the event of a vehicle crash, inertia causes a passenger to be thrown forward into the seat back in front of that passenger, and a walkover seat back receiving the impact of the passenger would, in response to that impact, move from the rest position it was in at the time of impact toward the opposite rest position of the seat back. A seat back is normally inclined, i.e. the angle of the seat back is displaced from true vertical. As a walkover seat back moves from one rest position to the other rest position, in response to impact by a passenger, the angle of inclination changes from a rearward inclination to a frontward inclination. As a result of this change in inclination, the seat back acts as a ramp for the passenger who has impacted against the seat back and directs the passenger frontwardly and upwardly into the overhead structure, e.g. an overhead luggage rack or the floor of an upper level of seating in a bi-level car. This increases the potential for injury to the passenger.
One attempt to eliminate the problem described in the preceding paragraph was to fix the seat back against walkover movement. This proved to be very unpopular with passengers, most of whom preferred to face forward when the vehicle was in motion. In addition, it eliminated the flexibility of group clusters, which was available with walkover seat backs.
Another attempt to solve the problem was to provide the walkover seat with a locking mechanism which normally locked the seat back against walkover movement but which could be unlocked with release handles or pedals, but this too had drawbacks. A seat employing the locking mechanism was considered to be not user friendly. Passengers unfamiliar with the locking system had to hunt for the release handles or pedals. Manually unlocking the walkover seat back before moving it from one position to another required more complicated efforts on the part of a passenger or train personnel, and the need to perform these additional efforts slowed down considerably the speed with which train personnel could change the facing direction of all the seat backs in an entire car. The release handles or pedals, and the associated locking mechanism, were susceptible to damage, necessitating maintenance and repair procedures not previously required for walkover seats.
A serious drawback of both fixed seat backs and normally locked walkover seat backs was the increased impact load experienced by a passenger who impacted against a seat back which did not give or yield when impacted. Unlike an unlocked walkover seat back, a fixed seat back or a normally locked walkover seat back remained in place when impacted by a passenger who, as a result, experienced a greater impact load than did a passenger who impacted against an unlocked, walkover seat back.
An example of a walkover seat employing a locking arrangement with a release handle is disclosed in the aforementioned Kehl et al U.S. Pat. No. 4,407,542.